In recent years, also in a vehicle, a mechanical driving system tends to be replaced with an electrically driving system in order to satisfy requirements of a space-saving, an improvement of ease of assembly, an improvement of controllability and the like. For example, as shown in Patent Literature 1, a range-switching mechanism of an automatic transmission for a vehicle is driven by a motor. The range-switching mechanism is provided with an encoder which outputs a pulse signal at a specified angle in synchronization with a rotation of the motor. A feedback control is performed in such a manner that an energization phase of the motor 12 is sequentially changed according to a counting value of an output signal of the encoder and the motor is driven to a target rotational position (target counting value) corresponding to a target range, whereby a shift range is changed to a target shift range.
Moreover, in Patent Literature 1, when a failure of a feedback control system of the motor is detected, an open loop control is performed in such a manner that the energization phase of the motor 12 is sequentially changed and the motor is driven to the target rotational position, whereby the shift range is changed to the target shift range.
However, in such a case, it is likely that a switching completion time of the shift range may be delayed than a normal switching completion time (that is, a time period until a switching completion may become longer than a normal time period). In case that the switching completion time of the shift range is delayed than the normal switching completion time, it is likely that a driver may determine (misunderstand) that the shift range cannot be changed before the switching completion of the shift range and the driver may get off a vehicle. It is necessary to secure safety in preparation for such a situation.